Hoorah! I’ve just replaced the standard Postnuke RSS 0.91 RSS backend.php with the xBackends 2.6 from LEXeBus to give me an RSS 2.0 feed instead of the older 0.91 version.

The two minor hacks I did was to mimic the behaviour of the old backend.php so I could just drop it in as a replacement by setting the following variables at the top of the script:

$show_content=1;        // Default to showing the content of articles
$feedtype="rss2";       // Default to giving an RSS2 feed

With that done I get a successful validation via FeedValidator, viz: